Many times it is easier to do your own instead of trying to figure out what
someone else did. My Anilam systems simply had motors with tachometers
going to the drives and encoders going to the controls. Maybe you can use
some of your parts in your retrofit. For emergency stops it's nice to kill
the power to the drives but leave power on the PC and encoders so you don't
crash the PC and lose position everytime you have to hit the E-stop.
Have you thought of any G-code generating scripts you can write? Maybe
tapered pipe threading or spirals. When you get it ready perhaps you can
make me some jaws for my 3 jaw chuck, it would be a wonderful learning
opportunity for you :-) It would be kind of interesting to figure the
minimum and maximum radius for each tooth on each jaw spaced out at
120degrees, and write a program to cut the teeth to properly engage the
scroll. Or maybe just properly spaced dowel pins and lots of grease!
Anyway, I hope you have a fun and educational learning experience, maybe
your son will be interested too. It will be nice for you to know the
machine inside out, when there is a problem or you need an upgrade you'll be
able to handle it yourself. No $2K boards!
I've got two of the old chucks with non reversible jaws. Below is the
program to cut teeth for the 6" buck adjust true chuck. I make new softjaws
about 1/year and let this program run while I do something else. Its a very
old program, originally written for my DOS based Ahha control. I'd re-write
it for my modern Camsoft control, but it works. If it ain't broke, don't
;TEETH,ADJUST TRUE SOFT JAWS
;set second jaw back 0.100", third back 0.200"
%LAPPER = 0
%ZDEPTH = 0.5000
%COUNTER = 0
%ZDEPTH = %ZDEPTH + 0.025 *;DEPTH OF CUT FOR EACH PASS
%LAPPER = %LAPPER + 1
G92 X 0.00 Y 0.00 Z %ZDEPTH
G00 X 0.000 Y -0.250 Z 0.00
%COUNTER = %COUNTER + 1
G42 T 02
G01 X 0.008 Y 0.000 F 3.0
G01 X 0.122 Y 0.000
G03 X 0.096 Y 0.750 I -1.304 J 0.330
G01 X 0.000 Y 0.750
G02 X 0.008 Y 0.000 I -3.986 J -0.420
G01 X 0.008 Y -0.125
G01 G 40 X 0.2857 Y -0.25
G92 X 0.000 Y -0.25 Z 0.00
IF (%COUNTER LE 9) GOTO %LOOP
G00 X 0.00 Y 0.00 Z 0.00
IF (%LAPPER LE 5) GOTO %START *;DO ALL TEETH 5 TIMES
Roger, I thought about G code, but not too much. I know that I can
handle G code and generate it in fun way with perl and such.
My main concern right now is producing a system that is SAFE to
operate (properly takes all safety inputs into account) and that is
properly designed to be usable and not weird. Then I will try to make
sure that it is accurate by defining various parameters correctly.
I'm sure you can. I suspect your G code is going to be heavy into using macro
functionality since you are a coder. My first production PLC program didn't
most PLC programs because I wrote it like a guy used to procedural languages.
electrician thought my approach was a bit weird.
Make sure you have e-stops where you can get at them. Over travel limit
protect the axes. Sane parameters and circuitry so if the control system
is a problem, it can force an e-stop.
"Additionally as a security officer, I carry a gun to protect
government officials but my life isn't worth protecting at home
in their eyes." Dick Anthony Heller
my years as a corporate engineer upgrading old machine burned in to me that
safety is job 1.
All my CNC machines have two STOP buttons.
Estop kills the machine no matter what. Red palm buttons where ever you need
them and one Reset button operate a self latching master control relay
(MCR). Every device that moves something has a contactor or relay in front
of it and the control power comes from MCR.
There's actually a weakness in Estop as motors will coast to a stop, a
problem on huge machines. But you need it in case something got done
incorrectly somewhere (work in a corporation and you wouldn't believe how
much this happens)
So, there's also a Machine stop. These buttons are red and smaller and
placed near the Estop and also machine start and anywhere else that makes
sense. This button uses the control to bring in brakes and stop the machine
quickly. Do things like a brake resistor on your VFD, inhibit on your servo
drives, have the control also issue spindle off, axis stop (covers a lot of
mistakes if you stop things two or more ways)
Just my two cents
I don't know yet Wes. Maybe I will make G codes with procedural
languages. If so, then G codes will look kind of dumb.
I agree. I think that my plans are solidifying a little bit.
My first priority is installing encoders, and hooking them up to Jon's
PPMC box and that, to CNC. The axes would not be powered by servo
I will make up a little mill control, from a little DC power supply,
X-Y-Z selector, and On-Off-On switch, hooked up to the servos.
I would operate this control manually by hand.
With that, the mill will be manual controlled and will use PPMC as
just a DRO display.
The objective here would be to see if all the iron works, to debug all
estop logic, limit switches, inhibits, etc. The mill will be 100%
manually operated, but with the PC and PPMC working as a DRO.
Then I will try to fit it with a VFD.
At that point, it could be used for milling, like a regular Bridgeport.
I would then make sure that all auxiliary things run correctly, like
speed control air valves, coolant etc.
The next step would be to hook up the drive power supply (military
battery charger) and AMC servo drives and imlpement proper automatic
The advantage of this is that I could spend a couple of weeks
debugging this mill's safety and other functions, being almost 100%
safe due to manual control of the positioning.
Wrong. You won't be able to use this like a regular Bridgeport because
you won't have control to stop on a precise DRO position, nor will you
have the load feedback the manual handwheels provide. All you will be
able to do from a practical perspective is confirm that the limit
switches and encoder are working properly.